The Ring Cycle operas, perhaps his greatest works, were composed and first staged in 1876, shortly after Germany unified

He started the story outline in 1848, composed it through the years to 1857, put it aside for 12 years and finished it in 1869. The premiere of the complete cycle was in 1876, but sponsored by Mad King Ludwig of Bavaria, who was not exactly motivated by bourgeois nationalism.

A nationalist reading of The Ring is way too reductive. The myths he used are found all over the Teutonic world, most explicitly in Scandinavia. There are no German placenames in it except for a mention of the Rhine. It just doesn't make any sort of statement about how Germans ought to pull together, in the way Verdi's operas do for Italians.

You might be able to argue that one initial impetus was the revolutions of 1848, but any political content got so transmogrified as the work progressed that no simple slogans are discernible in it.